THE IRON-BACTERIA 



each of the rods. In the younger stages if the 

 removed the sheath would appear as a uniform 

 tube divided up into compartments by means of 

 walls (fig. 6 and Plate VI). Each compartment 

 single rod. A little farther on in the development 



383 



rods were 

 cylindrical 

 transverse 

 contains a 

 the sheath 



Cladothrix dichotoma ; x 1,000. 



FlG. 6. — Cladothrix dichotoma ; x 3,000. 



a, rod-cell ; b, wall of rod-cell ; c, lateral wall of sheath ; 

 d, transverse wall of sheath ; c, thick transverse wall 

 indicating spot formerly occupied by rod-cell. 

 Latter escapes laterally, the space occupied by it 

 being gradually encroached upon by the growth 

 and division of the lower rod-cells. 



Fig. 5. 



Fig. 6. 



hardens, and while this is taking place the basal rods are divid- 

 ing and elongating, and by the pressure of their growth forcing 

 themselves upwards. The result is that the transverse walls 

 are broken and obliterated, and an opening is effected at the 

 apex (fig. 7, B). The sheath therefore becomes a hollow, more 

 or less firm tube, permanently open at the top. In the final 

 stage we see nothing but a hollow sheath from which all the 



